Hammer



Dec. l2, 1950 H. H. TALBoYs ETAL 2,533,975

ff Y Dec. 12, 1950 H. H. TALBoYs ETAL 2,533,975

lor slots through which the shaft 5 passes. the form of Figure l, we illustrate a plurality of Patented Dec. 12, 1950 HAMMER Henry H. Talboys and Helmer E. Erickson, Milwaukee, `Wis., assignors to Nordberg Manufacturing Co., Milwaukee, Wis., a corporation of Wisconsin Application April 15, 1946, Serial No. 662,173

One purpose is to provide an improved power hammer.

Another purpose is to provide an improved 4power hammer and anvil assembly.

Another purpose is to provide an improved hammer element for use with power hammers.

Another purpose is to provide an improved anvil element for use with power hammers.

Other purposes will appear from time to time in the course of the speciiication and claims.

The invention is illustrated more or less diagrammatically in the accompanying drawings, wherein:

Figure 1 is a section on a plane perpendicular- `to the axis of rotation of the hammer assembly;

Figure 2 is a section on the line 2--2 of Fign ure 1;

Figure 3 is an enlarged view of the opposed `parts of the hammer element and anvil;

Figure 4 is an elevation of a variant hammer element;

Figure 5 is a section of a variant hammer element Figure 6 `is a vertical section illustrating thedriving vconnection for the hammer assembly illustrated in Figures 1 and 2; and

Figure '7 is a section similar to Figure 1 illustrating -a variant form of the device.

Like parts are indicated by like symbols throughout the speciiication and drawings.

Referring to the drawings I generally indicates any suitable housing or frame in which a hammer rotor assembly is rotatably mounted, for example.

in roller or ball bearings 2. 3 indicates a shaft, the ends Aof which are rotatably in the bearings 2. Mounted on it is a rotor or cage which may include a pair of spaced discs 4, 4a, separated by suitable 5 Claims. (Cl. M55-33) spacing elements 5 and carrying a plurality of: y

bearing pins 6. 'I is any suitable beveled friction drive member which may be formed as an extension from the disc 4, or may be otherwise formed. Rotatably mounted on the shaft 6 are individual hammer elements 3. Each such elef" ment is in the form of a Adisc having a generally cylindrical impacting face 9 cut away or flattened, preferably at two diametrically opposed points as at I6, Illa. Each disc 8 is provided with a slot In.

slots or slightly elongated apertures II, Ila: In the form of Figures 4 and 5 we illustrate a single elongated slot, I Ib in Figure 4 and I Ic in Figure l 5. It will be understood that as the hammer assembly rotates, the hammer elements 8 move centriiugally outwardly as far as the slots Ila, `I Ib or I I c permit. They are also free to rotate about the pins 6. They are so positioned that, when the rotor rotates, in the direction of the arrows in Figure 1, the arcuate surface adjacent and in advance of the cutaway portion IIJ, constitutes an impacting surface effective to engage the below described anvil, which is odset ysomewhat from the axis of the rotor.

I5 generally indicates a guiding sleeve in which is slidably positioned a hammer element or blow delivering member shown as including the ham'- mer head I6 and the anvil structure I1. `The anvil is 'laterally enlarged as at I8, the enlarged portion being received in the upper enlargement I9 of the sleeve I5 and the opposed adjustable nut 20. The members I9 and 20 are mounted vfor relative adjustment within the screw threaded split sleeve 2|. The sleeve 2l is held by bolts 22 Yin any suitablelower extension 23 of the housing I. It will be noted that the anvil I'I extends upwardly through the nut 20 and opposes an inclined face 30 to the hammer element 6. The parts are shown on an enlarged scale `in Figure 3 and it will be observed that the toe or end of the arcuate impacting surface 9 engages the inclined surface 30 of the anvil. It will be `understood that the anvil I'I may be reversed to present `the opposite inclined surface 30a `tov the hammer elements. Also, the individual hammer elements B may be reversed on the pins 6. There.` is .thus a double provision for wear, which extends 'the life oi the opposed wearing parts.

Any suitable means may be employed for rotating the hammer assembly. As a matter of convenience however, and as a orin of practical drive, we illustrate in Figure 6, a drivngassembly including a shaft 50 mounted in any suitable bearings 5I within a housing 52. The shaft 50 may be rotated for example by a flexible shaft 53 extending to any suitable motor not herein shown. l

The shaft carries at its outer end the frictional disc 54 which is opposed to the frictional driven member 1. The housing .52 is mounted within a housing 55 and is spring thrust, as 'by the coil spring 56 to maintain compression between the members l and 54. The thrust of the spring 56 may be adjusted or controlled by any suitable takeup member or spring abut-ment 51, screw threaded as at 58 'in relation to the .ad-

. justing sleeve 59 which extends outwardly from It will be realized that whereas we have described and illustrated a practical and operative device, nevertheless many changes may be made in the size, shape, number and disposition of parts without departing from the spirit of our invention. We therefore wish our description and drawings to be taken as in a broad sense villustrative or diagrammatic, rather than as lim# iting us to our precise showing.

For example either a single slot may be employed in the hammer elements, as shownin Figures 4 and 5, or separate or interrupted slots may be employed, as shown in Figure 1. The impact members 8 may be unitary, as shown for example in Figures 1 and 4, or they may be formed with a separate outer removable wear taking member 8a as shown in Figure 5.

With references to Figure 7, we illustrate a form of hammer in Iwhich in the place of the form of rotor l! shown in Figure l, we illustrate a crossbar 'lil mounted on the shaft 3a, said cross bar having cross pins a, 6b adjacent opposite ends thereof. On the pins 6a we illustrate a h-ammer member fla with opposite arcuate hammer surfaces 9a and opposite flattened or out away portions lb, lic.V The hammer as shown is provided with two apertures each somewhat elongated as at Hb, Hc. The anvil structure including the anvil l 'i is the same as shown in Figure 1. At the opposite end of the cross bar of the rotor, we illustrate a counterweight 80 which is fixed against rotation, and which is so formed and positioned as to avoid any contact with the anvil. It -may be adjusted as to weight for example by employing apertures 80h which may have weights or fillers 80e inserted therein toa desired total weight.

i The use and operation ofthe invention are as followsz- We provide an efficient rotary hammer member 4 .particularly adapted for use with power driven hammer assemblies. The rotation of the rotor is effective to maintain the individual hammer ele- -ments 3 or ila. in their outermost position. With the Yparticular elements herein shown flattened 'as at l0 and lila, and with the ilattened parts related, as shown in the drawings, to the center vabout which the hammer elements rotate, and to the slots il, ila, lib and llc, the hammer elements engage the anvil at the toe of the ham- .mer element, or at a terminal portion of the arvcuate face of the hammer located just in advance of the lead end of one of the cutaway portions I or Illa. The hammer structure is preferably constantly rotated at high speed. As soon as the anvil i1 enters the path of movement of the hammer element it is subject to a rapid succession of sharp shocks or impacts, the timing of the impacts being determined by the rate of rotation of Athehammer structure.

Assuming that the anvil Il is in a predetermined position, holding the working end I 6 against whatever' member or material is to beimpacted, the rotaryvhammer assembly is so positioned as to cause the path of the outer portions of the hammer elements 3 to intersect with the impact receiving face 3l) or 39a of the anvil. As

long as the rotary hammer structure is in the As each hammer element 8 strikes the pins 6. Thus a rotary and bodily inward somewhat as it passes across the surface of the anvil. 'Ihe hammer can recede somewhat toward the center of rotation of the hammer structure;

and it can also rotate somewhat about the pin 6. There is thus both radial and rotary relief. However, even though the hammer structure is constantly rotated, a predetermined relative movement of separation of the anvil and the center of rotation of the rotor is effective to terminate the series of impacts. In practice it is important to have the hammer assembly of substantial weight. The hammer blow against the anvil I1 tends slightly to raise the entire assembly, which then drops slightly by the time the next hammer is ready to strike the anvil. The rotation of the hammer structure maintains an absolute balance as long as the hammer does not contact the anvil. There is therefore no continuous nerve shattering vibration, such as results from the usual power hammer. However, when the parts are in contact, the eiect of the contact of the hammer elements on the anvil is to tend to lift the hammer assembly, the force being absorbed by the Weight of the hammer assembly, which rises upon contact, and falls again in time with the rapid contact which follows.

AThe hammer herein shown may be applied to a wide variety of uses. It may be employed in connection with tampers or cement breakers. It is ideally ladapted to driving spikes or nails, for example in railroad use. If made somewhat larger it may be employed as a pile driver.

Wherever in the form of Figure 1 we illustrate 0 four hammers, it will be understood that more or less than four may be applied, for example it may be advantageous to remove two opposite hammers, leaving two diametrically opposed hammers in position. This can be done without any change in the structure. The form of Figure 7 may also be advantageously employed with two hammers but we illustrate it as having one hammer and one counterweight.

`With reference to the operation of both forms herein shown and regardless of the number of hammers employed, all hammers are arranged in diametrically opposed pairs. Where a counterweight is used, a counterweight and hammer are arranged in a diametrically opposed pair. When the anvil Il is not contacted, the 4rotating element for the time being does not affect the rotor. This permits the oppositely disposed hammer or counterweight to `pull the entire assembly upward.

It is highly important that the hammers have the cut away portions shown at l0, Illa, Illb or 10c. In eiect the center of the shaft 3 is somewhat in advance of the axisrof the anvil I l when the impact takes place. The impact in the form of a somewhat glancing blow with a substantial downward component is on the toe or last inch or inch and a quarter oi the surface 9 as shown in Figure 3. The slope 35i may be made as steep as for example an angle of rive degrees. In elfect there is a camming action. The anvil is driven downwardly, and the hammer as a whole is movement of the hammer elements are both jerked upwardly by the above discussed temporary interruption of the centrifugal pull on the rotor of the impacting hammer. This in connection with the cut away l!) withdraws the hammer from alignment with or subsequent immediate contact by the anvil Il, and the anvil can rise or rebound after the stroke without recontacting the hammer. By the time the hammer makes another circuit it is in position to strike another blow and as before completing a circuit, resumed its balancing centrifugal pull on the device.

In practice, in some sizes of hammer, we find it highly advantageous to employ a single hammer and counterweight as shown in Figure 7, with a single hammering contact for each rotation of the shaft 3. The hammer strikes a blow and gets out of the way and at the speeds of rotation employed, the number of impacts per minute is ample to obtain the desired effect.

Whereas we illustrate a friction drive for the hammer, it will be understood that any other suitable driving means may be employed, the details of the drive not forming part of the present invention.

We claim:

1. In a power hammer assembly, a hammer housing, a hammer rotor mounted in said housing for rotation about an axis predetermined in relation to the housing, a hammer loosely pivoted to the rotor for oscillation about a pivot eccentric to the axis of the rotor, said hammer having a generally arcuate impacting surface, the pivotal connection of the hammer with the rotor being substantially eccentric in relation to the impacting surface of the hammer whereby, in response to centrifugal force the center of mass of the hammer, when the rotor is rotated, is located substantially radially outwardly beyond the pivotal connection between hammer and rotor, a guiding sleeve secured to said housing, and extending outwardly from the path of the hammer, an anvil movably mounted in said guiding sleeve, means for limiting said anvil to an excursion of predetermined length toward and away from the path of the hammer, said anvil having a surface which lies, when the anvil is at its closest approach to the path of the hammer, in position to receive a glancing blow from that part of the hammer most remote from the axis of rotation of the rotor, said harnmer being loosely pivoted on the rotor and being thereby adapted both to swing and to recede against centrifugal force, in response to the glancing impact of the hammer against the anvil.

2. The structure of claim l characterized by and including a plurality of hammers mounted for rotary oscillation on said hammer rotor.

3. The structure of claim 1 characterized by and including an eccentric pivot pin on the rotor,

, the hammer being apertured to receive the pivot pin, the hammer aperture through which the pivot pin passes being of greater length than the diameter of the pin.

4. The structure of claim 1 characterized by and including an anvil having a generally plane surface bevel slightly inclined to the path taken` by the outer portion of the hammer in the course of its rotary movement toward the anvil.

5. The structure of claim 1 characterized by and including a reversible hammer having opposite surface bevels, each of which is slightly inclined to the path taken by the outer portion of the hammer in the course of its rotary movement toward the anvil, said bevels converging on an intermediate portion of the hammer engaging surface of the anvil.

HENRY H. TALBOYS. HELMER E. ERICKSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 758,323 Lindquist Apr.` 26, 1904 904,868 Hansen Nov. 24, 1908 1,632,255 Wagner June 14, 1927 1,632,937 Wagner June 21, 1927 1,707,887 Wagner Apr. 2, 1929 1,824,955 Thompson Sept. 29, 1931 2,025,318 Trotter Dec. 24, 1935 2,233,913 Colestock Mar. 4, 1941 2,248,523 Francastel July 8, 1941 FOREIGN PATENTS Number Country Date 552,884 Germany July 2, 1930 

